In the 19th century through the 20th century it was the influence of the music of African-Americans which most set United States apart from that of Western Europe. While African-Americans were looked down on by the majority of European-Americans and their musical influences were looked down as low class if not semi-barbaric by many Americans trained in the European Classical music tradition as late as the 1930s, the music was wildly popular with the general public. The African banjo became common in many styles of US music in the 19th century. Stephen Foster, by far the most popular American composer of that century, incoporated many African American rhythmic notions into his songs. The Minstrel show was very popular, and was the first example of American music widely exported abroad.

Interestingly, some West-African melodies, such as "Lucy Long" and "Old Dan Tucker", were retained by white country musicians decades after they fell out of the repertory of the decendants of the Africans who brought the tunes over.

Prior to the late 19th century, U.S. music was dominated by occasional songs of great popularity. Exampes include "The Star Spangled Banner", "Dixie" "Jump Jim Crow", "Oh Susana", "Oh My Darling, Clementine", "The Old Folks at Home", "My Old Kentucky Home", "Battle Hymn of the Republic[?]", "Just Before the Battle, Mother", and "When Johnny Comes Marching Home Again".

In the later decades of the 19th century, the music industry became dominated by a group of publishers and song-writers in New York City that came to be known as Tin Pan Alley. Tin Pan Alley's representatives spread throughout the country, buying local hits for their publishers and pushing their publisher's latest songs. Song demonstrators were fixtures at department stores and music stores in all cities and large towns, and traveling song demonstrators made circuits of rural areas. The industry was driven by the profits from the sales of sheet music. A piano was considered a must in any middle-class or higher home, or any home that aspired to be middle-class. Major 19th century Tin Pan Alley hits included "Only A Bird In A Guilded Cage" and "After The Ball Is Over".

In the 1890s, more sophisticated African American styles of the cakewalk and then ragtime music started to become popular. Originally associated primarily with poor African Americans, ragtime was quickly denounced as degenerate by conservatives and the classically trained establishment. In spite of the denigration, however, the style continued to gain widespread popularity and became was mainstream and was adopted by Tin Pan Alley at the start of the 20th century.

Military type marches enjoyed great popularity, and most towns had brass bands that performed them. The most popular of the march composers was John Philip Sousa.

In the beginning of the 20th century, the Tin Pan Alley popular song dominated the nation's music. Songwriters like Harry Von Tilzer, George M. Cohan, and Irving Berlin produced many catchy melodies early in the new century. Trailing behind were four other significant genres. African American jazz and blues performers diversified their sound and managed to achieve some success among white Americans. Folk and country music dominated the sound of rural white performers, and both managed to achieve some mainstream success. All five of these types of music influenced each other.

With the 20th century, the rise of the popular home phonograph began to give competion to the long dominant Tin Pan Alley sheet music publishers, and slowly became a significant force in United States music by the 1910s. In the 1920sradio broadcasts of music came on the scene, and together with the recording industry surplanted the sheet music publishers as U.S. music's driving force in the 1930s. In a parallel development, individual performers became more associated with hit songs in the public's mind than the songwriters.

In addition to jazz, blues, folk and country, music from the Caribbean region also briefly became popular during the first half of the twentieth century. Calypso and merengue and other styles influenced American popular music. Hawaiian music (esp. slack-key guitar[?]) enjoyed an early vouge in the 1910s, influencing the developing genre of country music (this is the source of the steel guitar sound that is characteristic of modern country).

The blues began in rural communities, primarily in the south. During the 1920s, female blues singers like Mamie Smith ("Crazy Blues") dominated the genre's sound. For most white Americans, these female singers were their first exposure to black music, or "race music" as it was then known. In the 1930s, local blues styles developed in Memphis, Texas[?], Kansas City[?] and, most importantly, Chicago. A style of piano-playing based on the blues, boogie woogie was briefly popular among mainstream audiences and blues listeners.

Billie Holiday

Jazz was more urban than the blues. Relying more on instrumentation, the sound was well-suited for listeners unfamiliar with the genre's conventions. In the 1920s, jazz bars became popular among white Americans, particularly young ones. Like with ragtime before, and most major genres since, jazz was blamed for the moral degeneracy of the youth that visited these bars and listened to the music. In spite of the controversy, jazz emerged as the dominant sound of the country in the late 1920s in popularized forms that some called watered down, like swing music and big band. Though these, like jazz proper, had been blamed for crime and delinquency, they had become mainstream by the 1930s. In the 1940s, pure jazz began to become more popular, along with the blues, with artists like Ella Fitzgerald ("A-Tisket, A-Tasket") and Billie Holiday ("Strange Fruit[?]") becoming nationally successful.

In the 1940s, the major strands of American music combined to form rock and roll. Based most strongly off an electric guitar-based version of the Chicago blues, rock also incorporated jazz, country, folk, swing and other types of music; in particular, bebop jazz and boogie woogie blues were in vogue and greatly influenced the music's style. It had developed by 1949, and quickly became popular among blacks nationwide (see 1949 in music). Mainstream success was slow to develop, though (in spite of early success with Bill Haley & the Comets[?]' "Rock Around the Clock"), and didn't begin in earnest until Elvis Presley ("Hound Dog", a white man, began singing rock, R&B and rockabilly songs in a devoted black style. He quickly became the most famous and best-selling artist in American history, and a watershed point in the development of music.

In the late 1960s, popular music underwent a sea change. Psychedelia-inflected rock dominated black and white audiences. During this period, most of American musical styles for the next forty years began in one form or another, including heavy metal, punk rock, electronic music and hip hop. Perhaps most importantly were two developments. First was the popularization of the LP as a distinct artistic statement. Prior to the early 1960s (and later in most cases), an LP was nothing more than a collection of singles bound together with filler. As the psychedelic revolution progressed, however, lyrics grew more complex and LPs developed to enable the artists to make a more in depth statement than a single song could allow. In addition, rules as to what could be allowed in popular music were lessened -- singles lasted longer than three minutes (Bob Dylan's "Like a Rolling Stone[?]" was the first of these); singing could be gruff, guttural and not classically beautiful and lyrics could focus on more than simple tales of youth, love songs and ballads to include politically and socially aware lyrics. The idea that popular music could and should change the way one feels and lead social change largely developed during this period, though it was certainly not unheard of before.

The mid-1970s saw the development of power pop, the marriage of glam and heavy metal to form hair metal and the emergence of disco. By the late 1970s, disco, an electronically-based dance music, dominated the sound of the US, aided by the breakthrough success of Saturday Night Fever. Originally associated with urban blacks and gay white males, disco spent a few years at the top of the charts just as country rock and prog rock achieved their greatest mainstream success. Country rock bands like Lynyrd Skynyrd (Second Helping[?]) and pop-prog bands like Chicago (Chicago II[?]) and Styx (Kilroy Was Here) dominated the portion of the market not listening to disco with long, bizarre progressive pieces and electric blues based southern rock. Country rock had developed primarily from British blues, and added an element of popular country. At the time, outlaw country[?] artists like Willie Nelson (The Red Headed Stranger[?]) and David Allan Coe ("You Never Even Called Me By Name") dominated the country music charts with tales of cowboys and rebels.

In the 1980s, punk music began incorporating reggae, ska and other international influences, while heavy metal diversified in the wake of the success of hair metal. Thrash, death and power metal emerged. Pop bands like U2 (The Joshua Tree) and R.E.M. (Murmur[?]) also led an interest in the alternative rock scene. All around the country, pop- and hard rock-oriented bands evolving in a state of popular dismissal but critical acclaim had developed a unique sound. Bands like the Pixies (Doolittle) and Hüsker Dü (New Day Rising[?]) made only minor waves on the charts, but fomented a serious revolution in music. A new generation of listeners hated the bombastic, corporate sterility of formulaic hair metal bands, and reacted against them.

The result was the grunge explosion in the early 1990s. By 1992 (1992 in music), hair metal bands were massively unpopular as grunge groups like Nirvana (Nevermind), Pearl Jam (Ten) and Alice in Chains (Dirt) dominated the charts. Their success lasted only a few years, however, as bands found it difficult to maintain their "alternative" sound after going mainstream. In addition, former N.W.A. member Dr. Dre (The Chronic) brought gangsta rap to pop audiences. By the mid-90s, alternative rock groups had died out among mainstream listeners, and gangsta rap took over. The middle of the decade also saw a boom in techno music's popularity. Developed primarily in Britain (though Detroit and Chicago were also influential), techno's many permutations achieved some mainstream success throughout the last half of the decade. Bubblegum pop like the Spice Girls also returned after a decade of more-or-less dormancy during the period of hair metal and grunge, both highly opposed to clean, slick and shiny content.